When a Well Spirit is attacked by a cold-based attack, it takes 1 1/2 damage, or double subduing damage (qv). Well Spirits can be subdued, but subduing attacks do only 3/4 of the damage that would otherwise be inflicted. Two exceptions are cold-based attacks, which do double damage when subduing, and fire-based attacks, which cannot subdue. 25% of subduing damage is actual, the rest regenerates at a rate of 2 hp per round. The Well Spirit is subdued when it has lost all of its hit points as a result of subduing damage, or a combination of actual and subduing damage. A subdued Well Spirit will grant wishes. A subdued Well Spirit will remain subdued for 7 - 10 (d4 + 6) days after its subdual. After this time it will only stay with an adventurer if it is given at least 1,000 gp per hit dice of the Spirit, and a well to inhabit. The well must be at least 4 feet in diameter and 50 feet deep. The walls must be lined with stone, and the water must be reasonably clean.